USARTS

Description

The EVK1100 provides two USART Interfaces : Usart 0 and Usart 1
RS232 level converters provide proper voltage levels for compliance to the RS232 standard. Two RS232 connectors are available :

  • USART 0 : USART with full control(UART_0)
  • USART 1 : USART with modem capability (UART_1)


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Pinout

These two USART Interfaces are connected through level adapter to two DB9 connectors.
These have the following pinout:

GPIO Name Alternate function used
PA 01 U0_TX
PA 04 U0_CTS
PA 00 U0_RX
P4 03 U0_RTS
PA 05 U1_RX
PA 06 U1_TX
PA 08 U1_RTS
PA 09 U1_CTS
PB 23 U1_DCD
PB 24 U1_DSR
PB 25 U1_DTR
PB 26 U1_RI

see below the hardware schematic :

USART 0 Connection
USART 1 Connection

Back to the Known Issues Page before using USART interface.

Modem connection

With the fix explained just below, the cable to use to connect the EVK1100 USART 1 to any DCE is a male-male crossover DB9 cable with 9 conductors (+ shield) or any equivalent configuration (e.g. a female-female crossover DB9 cable with 9 conductors and 2 male-male straight DB9 gender changers), i.e.:

     MODEM|                          |EVK1100 USART1
       DCE|                          |DTE
     DB9-F|DB9-M                DB9-M|DB9-F
          |                          |
          |                          |
FGND Shield-Shield ----------  Shield-Shield FGND 
          |                          |
          |                          |
DCD      1-1 ---------------------> 1-1      DCD
          |                          |
          |                          |            
 TX      2-2 <---------  ---------> 2-2      TX
          |            \/            |
          |            /\            |
 RX      3-3 ----------  ---------- 3-3      RX
          |                          |
          |                          |
DTR      4-4 <-------      -------> 4-4      DSR
          |          \    /          |
          |           \  /           |
GND      5-5  ---------\/---------  5-5      GND
          |            /\            |
          |           /  \           |
DSR      6-6 ---------    --------- 6-6      DTR
          |                          |
          |                          |
CTS      7-7 <---------  ---------> 7-7      CTS
          |            \/            |
          |            /\            |
RTS      8-8 ----------  ---------- 8-8      RTS
          |                          |
          |                          |
 RI      9-9 > ------------------ > 9-9      RI

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